It is generally recognized that reduced delivery of oxides of nitrogen in the smoke of tobacco products is desirable. Therefore, a number of methods have been developed to reduce the levels of nitrogen oxide precursors, such as nitrates and nitrites, in smoking products. Among these are microbial-based methods where microbial metabolism of nitrogen-containing compounds is employed to remove them from the tobacco.
It is also generally recognized that the use of flavors, i.e., aroma-producing substances, which generate a taste typical to tobacco when the tobacco is being smoked, are highly desirable in smoking products. Such flavors can be obtained, for example, from amino acids which are subjected to the so-called Maillard reaction. The quality of the flavors obtained in this way depends upon the amino acids used. Once produced these flavors are applied to smoking products in appropriate quantities. Most preferably, flavors that originate in tobacco components themselves are employed to provide smoking products with a pleasant aroma and taste.